A systematic review of human and animal leptospirosis in the Pacific Islands reveals pathogen and reservoir diversity

Abstract

BackgroundThe Pacific Islands have environmental conditions highly favourable for transmission of leptospirosis, a neglected zoonosis with highest incidence in the tropics, and Oceania in particular. Recent reports confirm the emergence and outbreaks of leptospirosis in the Pacific Islands, but the epidemiology and drivers of transmission of human and animal leptospirosis are poorly documented, especially in the more isolated and less developed islands.Methodology/Principal findingsWe conducted a systematic review of human and animal leptospirosis within 25 Pacific Islands (PIs) in Polynesia, Melanesia, Micronesia, as well as Easter Island and Hawaii. We performed a literature search using four international databases for articles published between January 1947 and June 2017. We further included grey literature available on the internet. We identified 148 studies describing leptospirosis epidemiology, but the number of studies varied significantly between PIs. No data were available from four PIs. Human leptospirosis has been reported from 13 PIs, with 63% of all studies conducted in Hawaii, French Polynesia and New Caledonia. Animal leptospirosis has been investigated in 19 PIs and from 14 host species, mainly pigs (18% of studies), cattle (16%) and dogs (11%). Only 13 studies provided information on both human and animal leptospirosis from the same location. Serology results were highly diverse in the region, both in humans and animals.Conclusions/SignificanceOur study suggests that, as in other tropical regions, leptospirosis is widespread in the PIs while showing some epidemiological heterogeneity. Data are scarce or absent from many PIs. Rodents, cattle, pigs and dogs are all likely to be important carriers, but the relative importance of each animal species in human infection needs to be clarified. Epidemiological surveys with appropriate sampling design, pathogen typing and data analysis are needed to improve our understanding of transmission patterns and to develop effective intervention strategies.

Circulating genotypes of Leptospira in French Polynesia : An 9-year molecular epidemiology surveillance follow-up study

“…Leptospira serovars or serogroups usually demonstrate specific host preferences [6]. Our findings are in agreement with our current knowledge of host preferences: i.e.…”

“…This study focuses on French Polynesia (FP) which is a French Overseas Country consisting of 22 territories in the South Pacific Ocean encompassing 118 atolls and islands [6]. Its overall population has been estimated to be 270,000 inhabitants.…”

Molecular and phenotypic characterization of Leptospira johnsonii sp. nov., Leptospira ellinghausenii sp. nov. and Leptospira ryugenii sp. nov. isolated from soil and water in Japan

“…Genetic characterization showed that the ribosomal 16S gene sequence of E8 is identical to that of L. neocaledonica isolated from soil in New Caledonia and that it belongs to the intermediate clade (Figure ). However, low variability and the conserved nature of the ribosomal 16S gene sequences among the Leptospira species have previously been reported . DNA–DNA hybridization in silico revealed that E8 is a member of intermediate species and differs from L. neocaledonica .…”

Potential sources of infection with selected zoonotic agents in the veterinary work environment – pilot studies

“…Leptospirosis is one of the most widespread worldwide, and the number of cases is estimated at approximately 1.03 million annually (including 58,900 fatal cases) [3]. Primarily, leptospirosis outbreaks appear in regions with a tropical climate (such as the Pacific Islands region), where frequent floods and heavy rains contribute to the development of infection [4].…”